Interface including a foam cushioning element

ABSTRACT

A respiratory mask assembly includes a frame having a channel and a cushioning element including a clip portion adapted for interference seal and retention in the channel. The cushioning element includes an interfacing portion constructed from foam and having a wider width than the clip portion.

CROSS-REFERENCE TO APPLICATION

This application claims the benefit of Australian Provisional PatentApplication No. AU 2008901056, filed Mar. 4, 2008, which is incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to an interface between a human and apiece of equipment, for example a mask, that includes a foam-basedcushioning element.

BACKGROUND OF THE INVENTION

In a number of fields, such as respiratory therapy, apparatus fordelivery of therapy includes a more rigid component defining a structureand a soft, cushioning component positioned between the patient and therigid component.

In the case of a respiratory device, the more rigid component may be amask frame defining a nose-receiving chamber. The mask frame may includea flange around its periphery. The cushioning component may be glued tothe flange. See U.S. Patent Application Publication US 2003/0168063.

The cushioning component may form an air tight seal with the skin of thepatient in some forms of respiratory therapy. In other devices, forexample headphones, it may not be necessary for an air tight seal to beformed.

Other known masks that include foam cushioning elements include thefollowing Fisher and Paykel masks: ACLAIM mask, FLEX-FIT 405, FLEX-FIT407, and FLEX-FIT 431.

SUMMARY OF THE INVENTION

A first aspect of the invention is to provide a patient interface with afoam cushioning element.

Another aspect of the invention is to provide a patient interface with aremovable foam cushioning element.

Another aspect of the invention is to provide a patient interface systemwith at least two different types of removably replaceable cushioningelements.

Another aspect of the invention is to include a cushioning elementhaving portion adapted for engagement with a more rigid component.

Another aspect of the invention is to provide a respiratory maskassembly including a frame and a cushioning element wherein thecushioning element includes a foam-based interfacing portion and a clipportion adapted for removable engagement with the frame portion.

Another aspect of the invention is to provide a support structure for acushioning element that supports the cushioning element on one side andallows movement on another side.

Another aspect of the invention relates to a cushion for a respiratorymask including a clip portion and an interfacing portion wherein theinterfacing portion is constructed from a foam material and the clipportion is narrower than the interfacing portion.

Another aspect of the invention relates to a respiratory mask assemblyincluding a frame having a channel and a cushioning element including aclip portion adapted for interference seal and retention in the channel.The cushioning element includes an interfacing portion constructed fromfoam and having a wider width than the clip portion.

Another aspect of the invention relates to a respiratory mask assemblyincluding a frame having a channel and a removably replaceableinterfacing structure including a clip portion adapted for interferenceseal and retention in the channel. The interfacing structure includes acushion component constructed from foam.

Another aspect of the invention relates to a mask system including acommon frame and at least a first cushion constructed from foam and asecond cushion constructed from silicone. The first and second cushionsare each structured to removably attach to the frame.

Other aspects, features, and advantages of this invention will becomeapparent from the following detailed description when taken inconjunction with the accompanying drawings, which are a part of thisdisclosure and which illustrate, by way of example, principles of thisinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings facilitate an understanding of the variousembodiments of this invention. In such drawings:

FIG. 1 shows a side view of a mask assembly including a foam cushioningelement according to an embodiment of the invention;

FIG. 2 shows a schematic diagram of a channel of a portion of a maskframe and a clip portion of a cushioning element retained by aninterference fit according to an embodiment of the invention;

FIGS. 3 a, 3 b, and 3 c show a range of rib engagement fittingarrangements between a mask frame and a clip portion of a cushioningelement according to embodiments of the invention;

FIG. 4 a shows a patient contacting side of a cushioning elementaccording to an embodiment of the invention;

FIG. 4 b shows a bottom view of the cushioning element of FIG. 4 a;

FIG. 4 c shows a top view of the cushioning element of FIG. 4 a;

FIG. 4 d shows a side view of the cushioning element of FIG. 4 a;

FIG. 4 e shows a frame contacting side of the cushioning element of FIG.4 a;

FIG. 4 f shows a patient contacting side isometric view of thecushioning element of FIG. 4 a;

FIG. 4 g shows a frame contacting side isometric view of the cushioningelement of FIG. 4 a;

FIG. 5 a is a plan view showing a die cut cushioning element wherein theclip portion includes a slot for engagement with the frame according toan embodiment of the invention;

FIG. 5 b is an isometric view of the cushioning element shown in FIG. 5a;

FIG. 5 c is an assembly view of the cushioning element shown in FIG. 5 awith a mask frame;

FIG. 6 a shows a cross-section from a prior art nasal mask with foamcushion;

FIG. 6 b shows a detail in the nasal bridge region of the mask of FIG. 6a;

FIG. 7 a shows an elevation view detail from the frame side of thecushioning element shown in FIG. 4 e;

FIG. 7 b is a cross-section along line 7 b-7 b of FIG. 7 a;

FIG. 7 c is a cross-sectional view showing the cushioning element ofFIGS. 7 a and 7 b in use; and

FIG. 8 is a cross-sectional view showing the assembly of the cushioningelement of FIGS. 7 a and 7 b and a frame according to an embodiment ofthe invention.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

The following description is provided in relation to several embodimentswhich may share common characteristics and features. It is to beunderstood that one or more features of any one embodiment may becombinable with one or more features of the other embodiments. Inaddition, any single feature or combination of features in any of theembodiments may constitute additional embodiments.

In this specification, the word “comprising” is to be understood in its“open” sense, that is, in the sense of “including”, and thus not limitedto its “closed” sense, that is the sense of “consisting only of”. Acorresponding meaning is to be attributed to the corresponding words“comprise”, “comprised” and “comprises” where they appear.

The term “air” will be taken to include breathable gases, for exampleair with supplemental oxygen.

Interconnection of Cushioning Element and Apparatus

In accordance with an embodiment of the present invention, a removableinterconnectable cushioning element (also referred to as a cushionelement or cushion) is provided. The cushioning element preferablyincludes a soft resilient foam interfacing portion for contacting ahuman. The cushioning element is constructed and arranged for removableinterconnection with the rest of the apparatus, for example arespiratory mask.

The ability to removably connect the cushioning element enables one toreplace the cushioning element should it become soiled and/oruncomfortable. It also facilitates trial of different forms ofcushioning element. One form of cushioning element, for example afoam-based cushioning element, may be used as a form of “training”system to allow a person to become accustomed to the sensation ofwearing and using a mask. A foam-cushion based mask may provide aninitially more appealing and comfortable surface for a new patient thana gel or silicone-based cushion. The patient may subsequently switchfrom the foam-based cushion to a silicone or gel based cushion. In thisway, the patient may be more likely to adhere to therapy because theyare used to the very soft comfortable feeling of foam.

When applied to respiratory equipment, the cushioning element is adaptedfor connection with a mask frame. In use, an air-tight seal is formedbetween the cushioning element and the frame. This arrangement could beused for both nasal and full-face masks.

For example, FIG. 1 illustrates a mask 10 including a mask frame 20 anda foam-based cushioning element 30 provided to the mask frame 20. Asillustrated, the foam-based cushioning element 30 provides a foaminterfacing portion 32 adapted to contact the patient's face in use. Inthis embodiment, the foam-based cushioning element 30 is adapted for usewith an existing mask (e.g., ResMed's Mirage Quattro mask), which allowsthe patient to switch from the foam-based cushioning element 30 to themask's existing silicone-based cushion if desired.

Dual Foam Layers

In one form of device in accordance with an embodiment of the invention,the foam-based cushioning element has two layers, i.e., an interfacingportion and a clip portion.

In an embodiment, the interfacing portion or cushion is constructed froma soft unskinned resilient viscoelastic polyurethane foam. Such a foamis disclosed in PCT Publication Nos. WO 2008/011682, published Jan. 31,2008, and WO 2008/070929, published Jun. 19, 2008, each of which isincorporated herein by reference in its entirety. In one form, theresilient foam may be formed by a known method such as die cutting.

FIGS. 4 a to 4 g show a foam-based cushioning element 230 according toan embodiment of the invention. As illustrated, the cushioning element230 includes an interfacing portion or face-contacting portion 232 and aclip portion 234 provided to the interfacing portion 232. In thisembodiment, the clip portion 234 is adapted for an interference fit witha mask frame, and the width of the clip portion 234 is narrower than thewidth of the interfacing portion 232 (e.g., see FIGS. 4 e and 4 g).

In the illustrated embodiment, both an inside surface and an outsidesurface of the foam interfacing portion 232 are die cut. This typicallyresults in straight cut edges, much like a kitchen sponge. The cushionmay therefore have a square cross section.

In an embodiment, the clip portion of the cushioning element may beconstructed from a more rigid foam than the interfacing portion. Forexample, the clip portion may be formed from nitrogen blownpolyethylene, or some other clean, biocompatible foam having a finecell-structure. Alternatively, the clip portion could be made from someother polymer or rubber. In an embodiment, the clip portion is adaptedto form a cushion-to-frame engagement mechanism and to form a structuralsupport for the interfacing portion.

The two layers (i.e., the interfacing portion and the clip portion) maybe adhered to one another using polyurethane hot melt glue. Thisarrangement provides a one piece cushioning element with an interfacingportion adapted to engage the patient's face and a clip portion adaptedto interface with the mask frame.

Cushion-to-Frame Engagement Mechanisms

According to an aspect of the invention, the cushion-to-frame engagementand connection mechanism provided by the clip portion may include achannel-type engagement or rib-type engagement.

As shown in FIG. 2, the channel-type engagement includes a foam clipportion 34 that is adapted to be received within the channel 22 of amask frame 20 with an interference fit. The foam clip portion 34 extendsaround the entire perimeter of the cushioning element so as to form anair-tight seal and retention with the mask frame.

As shown in FIGS. 3 a to 3 c, the rib-type engagement includes a foamclip portion 34 with one or more slots 38 to receive inner and/or outerribs 23, 24 of the mask frame 20. For example, the slot to ribengagement may provide an inner frame rib engagement (see FIG. 3 a), anouter frame rib engagement (see FIG. 3 b), or an inner and outer framerib engagement (see FIG. 3 c). This arrangement provides a broader baseof support for the sealing foam.

FIGS. 5 a and 5 b illustrate a foam-based cushioning element 830including a foam interfacing portion 832 and a clip portion 834, andFIG. 5 c illustrates the cushioning element 830 provided to a mask frame20. As shown in FIGS. 5 a and 5 b, the clip portion 834 includes a slot838 adapted to receive a rib of the mask frame 20. Also, providing awider clip portion 834 allows more stiffness and structural integrity tobe provided to the clip portion, making the clip portion easier toassemble to the mask frame.

When structured to form an interference fit with the mask frame, theclip portion may have the following properties: appropriate rigidity(e.g., less than that of the frame and in one form more rigid than thefoam interfacing portion); non-porous; and/or low compression set (theamount of deformation expressed as a percentage of original dimensions)which a material retains after compressive stress is released (in thisway, the clip portion maintains its retention force during its usagelife).

Interfacing Portion Support Structure

In accordance with an embodiment of the invention, a range of differentarrangements of clip portions and foam interfacing portions may beprovided. For example, the width of the clip portion may match theinterfacing portion, the width of the clip portion may be less than thewidth of the interfacing portion, or the width of the clip portion maybe greater than the width of the interfacing portion.

When the width of the clip portion is less than the width of theinterfacing portion, the clip portion and interfacing portion may bearranged such that (i) the outer perimeter of the clip portion andinterfacing portion align (hides hardness of clip portion and providesdesired freedom of movement in the interfacing portion), (ii) the innerperimeter of the clip portion and the interfacing portion align, or(iii) neither the inner or outer perimeter of the clip portion and theinterfacing portion align.

Similarly, when the width of the clip portion is greater than the widthof the interfacing portion, the clip portion and interfacing portion maybe arranged such that (i) the outer perimeter of the clip portion andinterfacing portion align, (ii) the inner perimeter of the clip portionand interfacing portion align, or (iii) neither the inner or outerperimeter of the clip portion and the interfacing portion align.

In these different configurations with different relative widths, theclip portion provides different forms of support of the interfacingportion.

When the width of the clip portion is less than the width of theinterfacing portion and the outer perimeter of the clip portion alignswith the interfacing portion, the interfacing portion is more free toflex in regions not having a clip portion next to it than in regionshaving a clip portion adjacent to it. For example, where the interfacingportion overhangs the clip portion, that overhanging region of theinterfacing portion has more freedom to move. This arrangement can bemore comfortable and more able to adapt to different geometries of aperson, and provide the correct vectors to seal the interfacing portionagainst the face.

When used as part of a respiratory mask, it may be preferable that theinner portion of the interfacing portion overhang the clip portion. Inthis arrangement in use, the face of the patient may engage with anunsupported inner edge of the softer interfacing portion causing it tobend and conform to the individual patient's shape.

FIG. 7 a shows an elevation view detail from the frame side of thecushioning element 230 shown in FIG. 4 e in a nasal bridge region. Asshown in cross-section in FIG. 7 b, it is apparent that the width w2 ofthe clip portion 234 is less than the width w1 of the interfacingportion 232 and that the outer perimeter of the clip portion 234 and theinterfacing portion 232 are aligned. An advantage of this arrangement isillustrated in FIG. 7 c where in use the nose is able to push the innerperimeter of the interfacing portion 232 in the direction shown by thearrow, in a cantilever manner as well as compressing.

FIG. 8 is a cross-section showing the clip portion 234 of the cushioningelement 230 received within the channel 22 of a mask frame 20. It can beseen that the width of the clip portion 234 is less than that of theinterfacing portion 232, and that the outer perimeter surfaces 236 and238 respectively of the clip portion 234 and interfacing portion 232 arealigned while the respective inner perimeter surfaces 240, 242 areoffset.

This arrangement is in contrast to prior art cushions (such as theLifecare mask shown in FIGS. 6 a and 6 b) where the inner perimeter ofthe cushion C abuts the frame F, and hence it is not free to moveinwardly and can only compress.

In one form, a mask system may be provided that includes at least twodifferent forms of cushioning element chosen from the set of foam-basedcushion, silicone-based cushion, and gel-based cushion.

While the invention has been described in connection with what arepresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the invention. Also, the various embodiments described abovemay be implemented in conjunction with other embodiments, e.g., aspectsof one embodiment may be combined with aspects of another embodiment torealize yet other embodiments. Further, each independent feature orcomponent of any given assembly may constitute an additional embodiment.In addition, while the invention has particular application to patientswho suffer from OSA, it is to be appreciated that patients who sufferfrom other illnesses (e.g., congestive heart failure, diabetes, morbidobesity, stroke, bariatric surgery, etc.) can derive benefit from theabove teachings. Moreover, the above teachings have applicability withpatients and non-patients alike in non-medical applications.

1-11. (canceled)
 12. An interfacing structure for a respiratory maskassembly comprising: a relatively less rigid foam cushioning elementadapted to contact a face of a patient to form a seal therewith in use;and a relatively more rigid clip portion constructed and arranged to beremovably attachable to a frame of the respiratory mask assembly, and tobe attached to said foam cushioning element to form a one piecestructure therewith, wherein a width of said clip portion is less than awidth of said foam cushioning element, and said clip portion and saidfoam cushioning element are arranged to define a region of said foamcushioning element that overhangs the clip portion, and allows said foamcushioning element to cantilever and compress when pressed against theface of the patient in use, and further wherein said clip portion isconstructed and arranged to extend around the entire perimeter of saidcushioning element and to form an air-tight seal between said clipportion and the frame.
 13. The interfacing structure of claim 12 whereinthe foam cushioning element and the clip portion are adhered to oneanother.
 14. The interfacing structure of claim 12 wherein the foamcushioning element is constructed from an unskinned foam.
 15. Theinterfacing structure of claim 12 wherein the clip portion is adapted toform a structural support for the foam cushioning element.
 16. Theinterfacing structure of claim 12 wherein respective outer perimetersurfaces of the foam cushioning element and clip portion are aligned.17. The interfacing structure of claim 12 wherein respective innerperimeter surfaces of the foam cushioning element and clip portion areoffset.
 18. The interfacing structure of claim 12 wherein the clipportion is adapted to form an interference fit with the frame.
 19. Theinterfacing structure of claim 12 wherein the foam cushioning elementfurther comprises a skin.
 20. A respiratory mask system comprising amask frame and an interfacing structure as claimed in claim
 12. 21. Arespiratory mask system comprising a mask frame adapted to connect toboth (i) an interfacing structure as claimed in claim 12; and (ii) asilicone-based cushion or a gel-based cushion.
 22. A respiratory masksystem comprising a mask frame comprising an interfacing structure asclaimed in claim 12; and at least one of a silicone-based cushion and agel-based cushion. 23-34. (canceled)